Earlier quoted context omitted.
Hydrogen is a battery with very particular uses cases. In particular: hydrogen is bad for use cases with large numbers of charge/discharge cycles, because the "cost of inefficiency" is proportional to the number of such cycles. However, for use cases with small numbers of charge cycles, like seasonal storage or backup against rare grid outages, hydrogen's big advantage -- the low cost of storing it, vs. typical short…
Let’s assume at scale you’re buying seasonal power for 0$ so efficiency doesn’t matter and selling it at 10c/kWh given 1$/kWh and a once a year discharge you might break even in 10 years which looks fine except... 1$/kWh is only storage for already existing hydrogen. For this application you also need equipment to both produce and burn it which adds to these costs. Hydrogen generation can’t depend on 0$ prices for ve…
In the 100% renewable grid, electricity actually will be in surplus a good part of the time, because so much excess capacity would be installed. This is not the case now, so you can't use the current frequency at which curtailment occurs as some sort of baseline.
Yes, you'd need excess storage so it doesn't run out. Fortunately hydrogen storage is cheap. This is another argument for hydrogen over batteries.
You can run the numbers and see that in a hypothetical system for providing steady power in Germany, including hydrogen storage can cut the total cost nearly in half (subject to assumptions, of course.) Doing it with just wind, solar, and batteries ends up being far more expensive.